Boletín de aludes

East Slopes North

Northwest Avalanche Center
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Peligro de aludes

Tue
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 3 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

You may not get many warnings as signs of instability are waning, but wide and surprising avalanches remain possible, especially further east in the zone where the snowpack is more shallow. Use well supported terrain, and steer around steeper slopes with stiffer old snow. Another very cold day is on tap, so bundle up and bring extra gear to keep a bad situation from becoming worse. 

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    2–2.5

    Persistent slabs are trending less and less likely, but we call them persistent for a reason. It may take a larger load like a snomobile, or cornice drop to initiate them now, or a group of people staning in the wrong location. Any slide triggered would be surprising, and they can break widely across terrain features. Red flag signs of danger like shooting cracks and whumphing collapses are less likely to occur as we get further from last weeks storm, but the problematic snowpack structure remains.

    We recommend using safe travel protocol if you do decide to venture into steeper terrain. Only expose a person at a time to avalanche terrain. Stop and regroup in safer areas, well away from and out from under any steep slopes. 

    A weak crust/facet combination 2-3 feet below the surface. The further east you are from Washington Pass and the Cascade crest, the weaker and shallower the snowpack will be. Observers have reported whumphing collapses and other signs of these avalanches on Delancey Ridge. On the 9th, a number of natural avalanches likely ran on old weak layers near Cutthroat Lake (see photo). We believe those locations make up the western boundary of this problem. 

    (1/12/2024)

    Natural avalanches on Tamarack Peak, near Harts Pass. These likely occurred Jan 11th with northwest winds. We don't know exactly which layer these avalanches ran on, but they look suspiciously like persistent slab avalanches. E-SE, 7200ft

    Photo: NCH

Avalanche Discussion

Temperatures floated above 0 at Washington Pass on Sunday after buttoming out at -28 on Saturday. Winds have been fairly light, and we're not expecting much more than some light wind on MLK day. Strong winds on the 11th and 12th drifted a fair amount of snow and affected many snow surfaces, even at lower elevations. These wind slabs have become stubburn, but these are the areas to watch out for if the slabs rest over weaker layers.

Recent storm totals are about 2 feet since the 8th. On the 12th, an NWAC observer found some recent wind slab avalanches, one which may have stepped down to a weaker layer near Goat Peak. On the 12th an observer reported one collapse while skinning uphill on a supported feature of Delancey Ridge. On the 11th, multiple parties reported triggering small avalanches in recent storm snow and fresh drifts. Late in the day and overnight, natural avalanches ran due to northwest winds. Some of these may have stepped down to deeper weak layers, especially near Harts Pass and east. On the 10th, observers reported a number of large, natural avalanches over 2 feet deep near Cutthroat Lake (NE, ~6,800ft) that may have run on a crust from December 30th. That same day, observers on Delancey Ridge reported over 20 rolling collapses at all elevations on a similar crust/weak layer that developed during the prolonged dry periods in December. 

You may find up to 6 feet of snow on the ground at upper elevations near Washington Pass, with half that much in the mountains near Mazama. There are several decomposing crusts and layers of sugary facets that developed throughout December. In some locations, these layers present as individual layers; in others, they all meld together. Near and west of the Cascade crest the snowpack is deeper, has less weak layers, and the crusts are typically thicker and more stout.

If you're in the mountains, let us know what you see. Submit an observation here!

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